1. Field of Invention
This invention relates generally to adaptive optics systems and, more particularly, to alignment of adaptive optics systems.
2. Description of the Related Art
With recent advances in technology, there is an increasing interest in the use of free-space optical communications for various applications. Compared to other communications technologies, a free-space optical communications link can have advantages of higher mobility and compact size, better directionality (e.g., harder to intercept), faster set up and tear down, and/or suitability for situations where one or both transceivers are moving. Thus, free-space optical communications links can be used in many different scenarios, including in airborne, sea-based, space and/or terrestrial situations.
In many of these potential applications, the free-space optical communications link suffers from optical aberrations. For example, changes in atmospheric conditions can be a significant impediment to the accuracy, reliability and efficiency of free-space optical communications systems. Wind, heat waves, man-made pollutants and other effects can create constantly changing aberrations. This, in turn, can degrade the quality of the optical signal that is available at the receiver, resulting in degradation of the overall quality and efficiency of the communications channel. There is an increasing interest in using adaptive optics to correct for these aberrations, thus improving the performance and reliability of free space optical data transmission systems.
A free space optical communications terminal typically includes both adaptive optics components (e.g., wavefront sensor, deformable mirror, etc.) and data ports (e.g., data transmitter(s) and/or data receiver(s)). It is important to align the adaptive optics components and the data ports. The adaptive optics components and the data ports may be aligned initially during the manufacturing or building process of the terminal. However, the terminal may become misaligned after it has been deployed for use in the field. Over time, vibrations, temperature fluctuations and weather conditions can adversely affect the optical alignment of these components.
In addition, for certain applications, the terminal may be subjected to transient misalignments. For example, if a terminal is mounted on a vehicle that is traveling over rough terrain, the sudden jolts experienced by the vehicle may continuously misalign the components, thus requiring some sort of active alignment. In other applications, such as deployments on orbiting satellites or in remote locations, it may be difficult for a human to gain access to manually re-align the adaptive optics system and the data ports, thus favoring some sort of automatic alignment.
Hence, there is a need for approaches to align adaptive optics components and data ports. There is also a need for methods to align the adaptive optics and data ports remotely or automatically, without human intervention.